How many lights can I run on a circuit?

Posted on August 25, 2015.

It's important to never overload your electrical circuits, as they can overheat and create a fire hazard, or trip a circuit breaker and stop important equipment in your grow. To ensure you're being safe, you need to check what is plugged in already, and how much the circuit can handle. If you have any questions or doubts about your electrical setup, it is always best to consult a local electrician!

What kind of circuit?

Standard North American electrical circuits have different shapes for different circuit types, with outlets that looks like this:

110-120 volt, 15 amp
(NEMA 5-15)

110-120 volt, 20 amp
(NEMA 5-20)

220-240 volt, 15 amp
(NEMA 6-15)

220-240 volt, 20 amp
(NEMA 6-20)

Our PhytoMAX-2 LED grow lights come with an 8 foot power cord for 110-120 volt outlets (NEMA 5-15, compatible with NEMA 5-20); we have various length heavy duty power cords available for purchase as well.

Outside North America? All you need to run our PhytoMAX-2 lights is an IEC C13 (female) power cord of the right gauge that will work with your wall outlets, as long as you're between 100 and 277 volts. These are fairly standard computer and ballast cords and should be easy to find locally at a hydroponic shop, office supply or appliance store.

IEC C13 plug

What's on my circuit?

To determine what's on a circuit, you can turn off the breaker in the electrical panel and count all the electrical outlets (and things plugged into them) that stop working. Keep in mind they may not all be in one room!

What can I safely plug in?

Circuits are rated for different loads based on their amperage capacity. More amperage requires thicker wires to handle the extra flow of electricity. It is unsafe to rely on more than 80% of the capacity of any circuit; the wires may get hot or the breaker may trip. Some appliances such as fans, pumps and lights (including our LED grow lights) may require a bit more than their average electrical draw when they start up.

To ensure you're being safe plugging in your LED grow light, add up the wattage of everything you want to run on an LED light circuit. Divide the total wattage by the circuit voltage to get the number of amps, and make sure this is less than 80% of the circuit's rated capacity!